Twitter Responds to Performances From Kelly Clarkson, Sia on 'The Voice' Finale

Tuesday night's finale of The Voice brought tons of duets and solo performances from finalists and famous stars alike, like Kelly Clarkson, Sia, Jessie J and Bastille.

Fans of the singing competition loved the duet between Addison Agen and singer-songwriter Norah Jones.

Next up, contestant Noah Mac sang with Bastille.

Kelly Clarkson, who signed on as a coach for the next season of The Voice, took the stage for a solo performance and sang her new single, "Medicine."

Next up, superstar Sia took the stage with finalist Brooke Simpson to perform a powerful rendition of Sia's hit "Titanium."

Billy Idol joined finalist Chloe Kohanski for a rocking version of "White Wedding," much to fans' delight.

And just in case there weren't enough rock star vibes, Demi Lovato showed up to sing her hit "Tell Me You Love Me."

Jessie J re-claimed her spot on the stage (after singing with former contestant Chris Weaver and drag queen friends earlier in the show) to sing "Not My Ex" with former contestant Davon Fleming.

Finalist Red Marlow and country music icon Vince Gill injected the night with some country blues with Gill's hit "When I Call Your Name."